#include<iostream>
using namespace std;
const int N = 1010;
char a[N], b[N];
int f[N][N];
int n, m;
int main()
{
	cin >> n >> a + 1;
	cin >> m >> b + 1;
	for (int i = 0; i <= n; i++) {
		f[i][0] = i;
	}
	for (int i = 0; i <= m; i++) {
		f[0][i] = i;
	}
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			f[i][j] = min(f[i][j - 1], f[i - 1][j]) + 1;
			if (a[i] == b[j]) {
				f[i][j] = min(f[i][j], f[i - 1][j - 1]);
			}
			else {
				f[i][j] = min(f[i][j], f[i - 1][j - 1] + 1);
			}
		}
	}
	cout << f[n][m] << endl;
	return 0;
}